[INFO] updating cached repository torkeldanielsson/fraction_problems_generator
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/torkeldanielsson/fraction_problems_generator
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/torkeldanielsson/fraction_problems_generator" "work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/torkeldanielsson/fraction_problems_generator" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 4de0983a740f35130066c9eafd39386d82348861
[INFO] sha for GitHub repo torkeldanielsson/fraction_problems_generator: 4de0983a740f35130066c9eafd39386d82348861
[INFO] validating manifest of torkeldanielsson/fraction_problems_generator on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of torkeldanielsson/fraction_problems_generator on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing torkeldanielsson/fraction_problems_generator
[INFO] finished frobbing torkeldanielsson/fraction_problems_generator
[INFO] frobbed toml for torkeldanielsson/fraction_problems_generator written to work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator/Cargo.toml
[INFO] started frobbing torkeldanielsson/fraction_problems_generator
[INFO] finished frobbing torkeldanielsson/fraction_problems_generator
[INFO] frobbed toml for torkeldanielsson/fraction_problems_generator written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/torkeldanielsson/fraction_problems_generator/Cargo.toml
[INFO] crate torkeldanielsson/fraction_problems_generator already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing torkeldanielsson/fraction_problems_generator against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-0/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 1fa2de1d184ad0060c2ba54d0d7ece7cd0bc6166538b0e970e52f749661af743
[INFO] running `"docker" "start" "-a" "1fa2de1d184ad0060c2ba54d0d7ece7cd0bc6166538b0e970e52f749661af743"`
[INFO] [stderr]    Compiling math_gen v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:225:13
[INFO] [stderr]     |
[INFO] [stderr] 225 |         let mut a: i32 = rand::distributions::Range::new(3, 10).ind_sample(&mut rng);
[INFO] [stderr]     |             ----^
[INFO] [stderr]     |             |
[INFO] [stderr]     |             help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_mut)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.50s
[INFO] running `"docker" "inspect" "1fa2de1d184ad0060c2ba54d0d7ece7cd0bc6166538b0e970e52f749661af743"`
[INFO] running `"docker" "rm" "-f" "1fa2de1d184ad0060c2ba54d0d7ece7cd0bc6166538b0e970e52f749661af743"`
[INFO] [stdout] 1fa2de1d184ad0060c2ba54d0d7ece7cd0bc6166538b0e970e52f749661af743
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-0/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "test" "--frozen" "--no-run"`
[INFO] [stdout] b278615c040129616b89ab9c3732b74d0ff84a212333c60bd92fe6c2b0bf4916
[INFO] running `"docker" "start" "-a" "b278615c040129616b89ab9c3732b74d0ff84a212333c60bd92fe6c2b0bf4916"`
[INFO] [stderr]    Compiling math_gen v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]    --> src/main.rs:225:13
[INFO] [stderr]     |
[INFO] [stderr] 225 |         let mut a: i32 = rand::distributions::Range::new(3, 10).ind_sample(&mut rng);
[INFO] [stderr]     |             ----^
[INFO] [stderr]     |             |
[INFO] [stderr]     |             help: remove this `mut`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_mut)] on by default
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1.43s
[INFO] running `"docker" "inspect" "b278615c040129616b89ab9c3732b74d0ff84a212333c60bd92fe6c2b0bf4916"`
[INFO] running `"docker" "rm" "-f" "b278615c040129616b89ab9c3732b74d0ff84a212333c60bd92fe6c2b0bf4916"`
[INFO] [stdout] b278615c040129616b89ab9c3732b74d0ff84a212333c60bd92fe6c2b0bf4916
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-0/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/torkeldanielsson/fraction_problems_generator:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "test" "--frozen"`
[INFO] [stdout] b34bdc39581016ece7766da4ac805177f1bfd0b9e323f1389ca56e1f5000306d
[INFO] running `"docker" "start" "-a" "b34bdc39581016ece7766da4ac805177f1bfd0b9e323f1389ca56e1f5000306d"`
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.05s
[INFO] [stderr]      Running /opt/crater/target/debug/deps/math_gen-c4de5715f9f27c36
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "b34bdc39581016ece7766da4ac805177f1bfd0b9e323f1389ca56e1f5000306d"`
[INFO] running `"docker" "rm" "-f" "b34bdc39581016ece7766da4ac805177f1bfd0b9e323f1389ca56e1f5000306d"`
[INFO] [stdout] b34bdc39581016ece7766da4ac805177f1bfd0b9e323f1389ca56e1f5000306d